|As I read your brief "specs." info above you seem to running XP is 64bit mode?|
What make and model of KVM are you using…?
Are the keyboard/mouse usb or ps2 connection?
Just to clarify: you're running one monitor and one keyboard and mouse for two XP computers - via a KVM switch?
Which means two monitor inputs (one from each PC), one monitor output - to the single monitor; two keyboard and mouse "output" connections (one each to each PC) and one keyboard/mouse "input" connection for the user… and which control whichever pc is selected?
If you connect each PC in turn to just one of the two sets of PC connections for mouse/keyboard (i.e. use the same, just one, of the PC mouse/keyboard outputs for each PC in turn…) what happens; and if you then repeat both PCs connected to the other/the second set of (output) connections (for mouse/keyboard) what happens?